An endoscope or other type of scope for use in medical applications generally is a medical instrument with a shaft with optics (such as one or more fiber optic cables) that carries light to and from the interior of a patient's body to allow an operator of the scope to visualize that interior. A scope typically is used by an operator during a minimally invasive medical procedure, in which a distal portion of the scope is inserted into the patient's body through a natural orifice of the patient's body or through a small incision made in the patient to gain access to the patient's interior. A scope typically has one or more working channels extending through the proximal handle and through the shaft to the distal end of the scope. The channel(s) can carry medication, fluids, air, and/or surgical instruments. A scope can be used in minimally invasive procedures requiring visualization of, access to, and treatment of one or more interior portions of a patient's body such as the gastrointestinal tract, nasal cavity, sinuses, pharynx, tracheobronchial system, genitourinary tract, uterus, peritoneal cavity, pleural cavity, and subfascial spaces.
Various mechanisms for deflecting the distal portion of a scope or other medical instrument are known. Pull wires or cords running along the shaft of the instrument can be used to bend the distal portion. Such pull wire or cord arrangements tend to pull the distal portion of the instrument in a non-planar direction and cause one or more other portions of the shaft of the instrument to buckle or form a series of “S” shapes from the tension of the pull wires or cords. Also, integral pull-wire deflection arrangements may require the user to turn or twist the entire shaft to obtain additional degrees of freedom of movement of the distal portion. This kind of rotational movement can alter an image in undesirable ways.